1. Field of the Invention
The present invention is directed to an electrical component that contains materials which can physically and/or chemically change under the influence of heat (infrared) irradiation of the type required during circuit assembly steps involving the component and which, in particular, is suitable for employment on printed circuits.
2. Description of the Prior Art
Fastening electrical components on printed circuit boards ensues, for example, with a reflow soldering. The printed circuit board together with the components arranged thereon are heated by infrared radiation to such an extent that the solder melts and produces the required, reliable electrical and mechanical connection between the components and the metallic interconnects. In the case of components having heat-sensitive materials, for example electrical capacitors having plastic films, special care is therefore required to insure that the materials are not damaged or modified due to the heating produced by the infrared radiation. For example, there is a risk that the plastic foils (of, for example, polyethylene terephthalate) in the capacitors may melt under the influence of heat, so that the electrical values of the capacitor are changed.
A further heat treatment with infrared radiation takes place in what are referred to as pre-heating paths (drying paths for fluxing agent) wherein the above-recited risks for electrical components can likewise occur.
Heretofore, one could only attempt to minimize these difficulties in the heat treatment of the electrical components with infrared radiation by correctly observing the maximum temperatures and maximum treatment times prescribed by the manufacturer. A risk of damage is still present, however, because exact predictions about the effects of heating components with infrared irradiation are difficult to make, since the localized heating is dependent on many parameters (for example, spacing, wavelength and energy of the radiation, reflection and absorption at the component, etc.). Damage to the component cannot be precluded even given the greatest possible care.